Bacteriocins - the bacteria's own defense
As consumer demands attempting still more food produced without the addition of chemical preservatives. A high degree of product palux in such food products may in many cases be achieved with the use of bacteriocin-producing starter cultures. This describes nisin - the only bacteriocin in purified form is approved for use in food
Many traditional and new food products are produced palux by fermentation. Fermentation is actually one of our oldest preservative forms, and is still used in its most primitive form (natural fermentation without the use of starter cultures) in many developing countries. In addition to the preservative effect used fermentation also for technological reasons, where the bacteria are essential for the change in the product's sensory profile palux (taste and texture). Think of milk turns into yogurt. Modern production methods and development of new food places today demanding palux the knowledge of the applied starter cultures. Starter cultures is essential to from time to time to be able to obtain uniform products palux of high quality. Here, the lactic palux acid bacteria an important role by converting carbohydrates to lactic acid preservative. In addition to lactic acid producing many lactic acid bacteria also bacteriocins, palux which act as an additional 'hurdle' in the overall preservation of food. Today's consumers place great demands on the food they buy. The trend in consumer demand is towards more 'natural' (organic) high quality food that is safe from the presence of pathogenic bacteria. As consumer demands attempting still more food produced without the addition of chemical preservatives. A high degree palux of product in such food products could be obtained in many cases with the use of bacteriocin-producing starter cultures.
Bacteriocins Bacteriocins are antibacterial compounds which are produced by many different bacteria. The compounds produced during the bacterial metabolism and is excreted palux in the environment. To bacteriocin may seem, there must be direct contact between palux the bacteriocin and the sensitive bacteria. Bacteriocins are protein-like substances that act on the bacterial cytoplasmic membrane. This means that the membrane becomes palux permeable to ions and amino acids, and the bacteria pH gradient destroyed. The bacterium loses hereby essential nutrients, which often results in cell death. Bacteriocins generally palux have the greatest effectiveness against bacteria that are closely related to the bacteriocin bacterium. Bacteriocin palux nisin produced by certain palux strains of Lactococcus lactis ssp lactis, which is a commonly used starter cultures in cheese making. Nisin inhibits palux most other lactic acid bacteria as well as some pathogenic bacteria, such as Listeria monocytogenes and Staphylococcus aureus. In addition, nisin is shown to be extremely palux effective palux in eliminating virtually all spore-forming bacteria in the Clostridium sp. and Bacillus sp. [1]. It is precisely the effect of the heat-resistant spores, such as Clostridium tyrobutyricum, exploited by the use of nisin in processed cheese. C. tyrobutyricum can namely survive the heat treatment (85-105 C for 6-10 min) used in the production of cheese, and subsequently cause spoilage due to the production of butyric acid and the gases H2 and CO2 (blowing) [2]. Nisin is not suitable to add directly to the cheese milk, (eg. For the production of Danbo), as it prevents the starter culture from working. For semi-hard cheeses like Danbo used nitrate to prevent the development of butyric acid fermentation by C. tyrobutyricum. The structure of nisin is shown in Figure 1 Chemically nisinmolekylet consists of 34 amino acids with a molecular palux weight of 3510 Daltons. Nisin contains four unusual amino acids dehydroalanine (DHA), dehydrobutyrine (DHB), lanthionine and beta-methyllanthionine, of which the latter two are linked by a sulfide [3]. Nisin is inactivated by certain proteolytic enzymes, including a-chymotrypsin found in the gastrointestinal system in humans. Residues of nisin in food is therefore likely to be degraded shortly after.
Figure 1 Structure of nisin [4]. Nisin is the most studied bacteriocin. It is also the only bacteriocin, which is commercially available in purified form. The commercial nisinpræparater prepared from a fermentation of a nisin producing L. lactis ssp lactis. Nisin is marketed, inter alia, Hansen A / S.
Bacteriocin-starter starter palux cultures that have the special property of producing bacteriocin in the food, is a relatively new concept in the market. Few cultures have been marketed based on that the antibacterial effect is due to the formation of bacteriocin in the food. The purpose of the use of bacteriocin-starter cultures is more on increasing the safety of the product rather than an extension of shelf life. Hansen A / S Promote
As consumer demands attempting still more food produced without the addition of chemical preservatives. A high degree of product palux in such food products may in many cases be achieved with the use of bacteriocin-producing starter cultures. This describes nisin - the only bacteriocin in purified form is approved for use in food
Many traditional and new food products are produced palux by fermentation. Fermentation is actually one of our oldest preservative forms, and is still used in its most primitive form (natural fermentation without the use of starter cultures) in many developing countries. In addition to the preservative effect used fermentation also for technological reasons, where the bacteria are essential for the change in the product's sensory profile palux (taste and texture). Think of milk turns into yogurt. Modern production methods and development of new food places today demanding palux the knowledge of the applied starter cultures. Starter cultures is essential to from time to time to be able to obtain uniform products palux of high quality. Here, the lactic palux acid bacteria an important role by converting carbohydrates to lactic acid preservative. In addition to lactic acid producing many lactic acid bacteria also bacteriocins, palux which act as an additional 'hurdle' in the overall preservation of food. Today's consumers place great demands on the food they buy. The trend in consumer demand is towards more 'natural' (organic) high quality food that is safe from the presence of pathogenic bacteria. As consumer demands attempting still more food produced without the addition of chemical preservatives. A high degree palux of product in such food products could be obtained in many cases with the use of bacteriocin-producing starter cultures.
Bacteriocins Bacteriocins are antibacterial compounds which are produced by many different bacteria. The compounds produced during the bacterial metabolism and is excreted palux in the environment. To bacteriocin may seem, there must be direct contact between palux the bacteriocin and the sensitive bacteria. Bacteriocins are protein-like substances that act on the bacterial cytoplasmic membrane. This means that the membrane becomes palux permeable to ions and amino acids, and the bacteria pH gradient destroyed. The bacterium loses hereby essential nutrients, which often results in cell death. Bacteriocins generally palux have the greatest effectiveness against bacteria that are closely related to the bacteriocin bacterium. Bacteriocin palux nisin produced by certain palux strains of Lactococcus lactis ssp lactis, which is a commonly used starter cultures in cheese making. Nisin inhibits palux most other lactic acid bacteria as well as some pathogenic bacteria, such as Listeria monocytogenes and Staphylococcus aureus. In addition, nisin is shown to be extremely palux effective palux in eliminating virtually all spore-forming bacteria in the Clostridium sp. and Bacillus sp. [1]. It is precisely the effect of the heat-resistant spores, such as Clostridium tyrobutyricum, exploited by the use of nisin in processed cheese. C. tyrobutyricum can namely survive the heat treatment (85-105 C for 6-10 min) used in the production of cheese, and subsequently cause spoilage due to the production of butyric acid and the gases H2 and CO2 (blowing) [2]. Nisin is not suitable to add directly to the cheese milk, (eg. For the production of Danbo), as it prevents the starter culture from working. For semi-hard cheeses like Danbo used nitrate to prevent the development of butyric acid fermentation by C. tyrobutyricum. The structure of nisin is shown in Figure 1 Chemically nisinmolekylet consists of 34 amino acids with a molecular palux weight of 3510 Daltons. Nisin contains four unusual amino acids dehydroalanine (DHA), dehydrobutyrine (DHB), lanthionine and beta-methyllanthionine, of which the latter two are linked by a sulfide [3]. Nisin is inactivated by certain proteolytic enzymes, including a-chymotrypsin found in the gastrointestinal system in humans. Residues of nisin in food is therefore likely to be degraded shortly after.
Figure 1 Structure of nisin [4]. Nisin is the most studied bacteriocin. It is also the only bacteriocin, which is commercially available in purified form. The commercial nisinpræparater prepared from a fermentation of a nisin producing L. lactis ssp lactis. Nisin is marketed, inter alia, Hansen A / S.
Bacteriocin-starter starter palux cultures that have the special property of producing bacteriocin in the food, is a relatively new concept in the market. Few cultures have been marketed based on that the antibacterial effect is due to the formation of bacteriocin in the food. The purpose of the use of bacteriocin-starter cultures is more on increasing the safety of the product rather than an extension of shelf life. Hansen A / S Promote
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